Friday, January 29, 2016

Asteroid 2016 BE Virtual Impactor for now in 2053

UPDATE 31/1/2016: The 2053 pass has been eliminated as a risk. There are still 5 virtual impacts from 2076 - 2111. These will also likely be removed as the precision of the orbit is improved.
Tonight, tracking potential virtual impactor Asteroid 2016 BE. Its a 79m wide Asteroid discovered on Jan 16th by the Catalina Sky Survey(703).
78 positions have so far been reported from 18 different observatories, including both H06 and I89, the iTelescope.net observatories. I managed to grab another 3 positions tonight. The asteroid is starting to speed up (in terms of relative velocity against the background stars) and tonight is moving quite quickly at 19 Arcsecs per minute. As a result of the fairly bright magnitude and the fast speed, you need to take as short an exposure time as possible. However the full moon is still pretty bright I had to use 30 sec images which means the asteroid is still slightly streaked. I have used a stacking technique to make sure my residuals are still reasonably good (given it is travelling at fairly high speed).
So what actually is a "Virtual Impactor". As asteroids are tracked the length of the recorded "arc" increases - now 10 days for 2016 BE. Of course the level of precision for future positions of the asteroid increases the longer the "known arc" and therefore the ability to determine future positions of the asteroid improves as the "zone of uncertainty" reduces. As long as the "zone of uncertainty" overlaps the earth's future orbit position, the object is listed as a virtual impactor for that pass. This happens from time to time without much concern, because as the precision of the orbit improves with more observations, the object usually drops out of the risk table quite quickly.
Whilst the asteroid will make a moderately close pass in the first week of February at 5.7 Lunar distances, its important to understand that the "virtual impact" currently listed in the Sentry Risk Table is for the 3rd February 2053 .... NOT ON THIS PASS!!!! As you would expect the "zone of uncertainty" for 2053 is much large than the "zone of uncertainty" for next week. So it will take many further observations before it is (most likely) removed from the risk table. Its current risk table score of Torino-0 just means that at this point the chance of a collision in 2053 has not been able to be eliminated at this stage.
Measured position:
K16B00E KC2016 01 28.46044 12 04 01.15 +65 50 49.0 16.9 R H06
K16B00E KC2016 01 28.46319 12 04 09.44 +65 49 54.8 17.3 R H06
K16B00E KC2016 01 28.46604 12 04 18.01 +65 48 58.7 17.4 R H06